G. B. THOMAS. ELECTRIC SNAP SWITCH.
Patented Oct. 1-3, 1896.
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GEORGE B. THOMAS, OF HARTFORD, CONNECTICUT, ASSIGNOR TO THE PERKINS ELECTRIC SIVITCII MANUFACTURING COMPANY, OF SAME PLACE.
SPECIFICATION forming part of Letters Patent No. 569,309, dated October 13, 1896. Application filed May 16, 1896. Serial No. 591,747- (No model.)
To all whom it may concern.-
Be it known that I, GEORGE E. THOMAS, a citizen of the United States, residing at Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Electric Snap- Switches, of which the following is a specification.
The invention relates to those electric snapswitches that have a rotary block bearing conducting-pieces that are adapted to make and break connection between stationary conducting pieces or brushes when the block is rotated.
The object of the invention is to provide a rotary block for such switches which will be simple and easy to manufacture and assemble and which when in position and in use will enable the switch to operate more efficiently and more uniformly with less wear on the parts and less danger of arcing or leakage than prior similar switches of this class.
Referring to the accompanying drawings, Figure 1 is a plan of one form of switch embodying the invention, the cover being removed. Fig. 2 is a plan of the base of the same, the handle, block, and brushes being removed. Fig. 3 is a section through the base and one of the contacts and brushes and through the block and one of the conductingpieces on the plane denoted by the broken line X X of Fig. 1. Fig. 4 is a plan of the block with the conducting-pieces in position; Fig. 5 is a plan of the block with the conducting-pieces removed. Fig. 6 is a view of one edge of one of the conducting-pieces, and Fig. 7 is a View of one side of the same.
The invention herein claimed is illustrated and set forth as embodied in a snap-switch constructed in the manner shown in United States Patent No. 517,100, dated March 27, 1894:, to which patent reference is made fora more detailed description of the operating parts referred to in this specification, if such is necessary.
In the views, 1 indicates the base of such a switch, which is usually a circular disk of wood, porcelain, or other suitable insulating material.
To the upper face of the base are fixed the stationary conducting contacts 2 and 3. These contacts are provided with means for attaching the circuit-wires, and either or all of them may .or may not, as desired, be formed as brushes having more orless spring. Loosely supported at the center of the base is a spindle 4., that may have any suitable form of handle by means of which it may be rotated. A part of the spindle is threaded and upon the thread is fitted a nut 5. Secured to the face of the base below this nut is a plate 6, that is provided with lookingteeth adapted to engage the end of the nut. Loosely connected with the nut is the rotary commutator-block 7, of insulating material, that bears the conducting-pieces 8, that con nect and disconnect the stationary contacts on the base. The impulse-spring 9 has one end connected with the spindle and the other with the nut.
When the handle is turned and the spindle rotated, the nut rides up the thread until unlocked from the locking-teethof the plate below and then the spring, which is thus made tense, throws the nut and commutatorblock with the conducting-pieces, as fully described in the patent referred to.
The commutatorblock is provided with slots 10 and sockets orindentations 11. These are preferably radial, the slots extending inward from the periphery from top to bottom of the block, while the sockets do not extend to the periphery and do not extend through the block. The commutator-block in the section that travels in the path of the brushes is slightly elevated or provided with bosses 12 midway between the slots and sockets.
The conducting-pieces 8 borne by the block are preferably formed of hard sheet-copper or a similar metal of good conductivity and some resiliency. These pieces are blanked into strips and bent to form practically hollow squares, the ends of the strips, however, not coming quite together, so as to leave one side of the squares open, as shown in Figs. 6 and 7. The ends of the' strips that project toward each other have portions cut away in such manner as to leave shoulders 13, that are adapted, when the pieces are in position,
to abut against the walls of the sockets in the block and prevent their removal. It is pre ferred to cut obliquely or bevel oil the ends of the strips, so that the openings between them will be tapering or wider on one side than the other, as shown in Fig. 7. \Vhen these pieces are in position, the ends project into the sockets in the faces of the block, while the sides opposite the ends of the pieces will lie loosely in the slots. The pieces are put in place by simply passing the hacks into the slots and crowding the ends onto the faces of the block until they come opposite and spring into the sockets provided for them. This is easily accomplished, for the beveled ends of the pieces gradually spread apart as they are pushed to position, but when the ends are opposite the sockets they spring into the sockets in such manner that the shoulders 13 will. abut against the outside ed gcs of the sockets and prevent the removal of the ends until they are again suiliciently sprung apart. The pieces cannot be easily removed, for, while they can be simply pushed on, in attempting to remove them the shoulders abut against the walls of the sockets and prevent removal until the ends are forcibly bent outward from the sockets, and there is no tendency to strain apart the pieces in this manner when they are in position, so that they will be very securely, although loosely, held in position against removal. These con d uctin gpieces, which are borne by the block, are easily stamped, readily bent, and quickly thrust to their places, from which they cannot be removed accidentally or by any wear or action incident to the use of the switch. The pieces are wide and flat, thus providing the proper extent of contact-surfaces. They have square breaking-lines when they, in movin with the block, leave the contacts and brushes, which reduces the liability of drawing an are after them. They are loosely held in place, which allows them to readily conform and adjust themselves to the spaces between the contacts and brushes and make good connections with both, regardless of any irregularity or iit of the block. They are somewhat yielding, that is, they have in themselves a little spring, which insures the wide flat surfaces making close joints with the contacts and brushes without requiring them to be jammed together hard, and they continue to make good and close joint with the contacts and brushes, even when the nut is being raised to unlock it and the spring made tense, until the block is snapped.
The bosses 12 on the faces of the block are so located as to rest between the contacts and brushes on the base when the switch stands with the circuit open. With this the switch operates more uniformly and regularly, for the brushes pass to and from them in the same manner as to and from the conducting-pieces, and as they ride under the brushes with some pressure they, after the break has been made,
. act as a drag and prevent the block and nut from rotating to such an extent as to give the teeth on the lockingplate a hard blow. These bosses also prevent the formation of a conducting-path of particles of copper worn from the conducting-pieces to where the brushes rest, for they lift the ends oi? the brushes from the face of the block. In the common form of switch the dragging of the brushes from the conductingpieces is liable after a time to form a path of conducting particles to such an extent as to allow a leak age of the current and the formation of an are along the surface of the block. These raised places or bosses wipe or scrape along on the faces of the contacts and under the brushes and thus keep them bright and clean, so a good contact is insured.
This invention allows the construction of a switch of this class in a much cheaper manner than formerly, and at the same time it insures a switch which will operate more efficiently, more satisfactorily, and more durably.
I claim as my invention-- 1. A switch having a base bearing contacts, a rotary spindle, a disk of insulating material connected to and movable with the spindle and having recesses in its upper and lower faces, and conducting-pieces of spring metal each formed in the shape of a hollow square with one side partially cut away, a part of each square ext-ending onto the upper face, a part extending onto the lower face and the parts of the cutaway sides that project toward each other extending into and loosely resting in the recesses in the upper and lower faces of the disk, substantially as specified.
2. A switch having a base hearingemitacts, a rotary spindle, a block of insuhiting material connected to and movable with the spindle and provided with slots and recesses, and connecting-pieces that are substantially hollow squares with one side split, loosely held by the block with parts extending through the slots and parts projecting toward each other and resting in the recesses, substan tially as specified.
A switch having a base bearing contacts, a rotary spindle, an insulating-block connected to and movable with the spindle and provided with slots and sockets, and. conducting-pieces formed in the shape oi. a hollow square with their ends entering and resting in the sockets and the sides opposite the ends passing through the slots, substantially as specified.
4t. A commutatonbloek for an electric snapswitch of the within-described class consisting of a disk of insulating material with slots extending inward from the periphery, sockets formed in the faces adj aeent to the slots, raised bosses on the faces between the slots and sockets, and eonducting-pieces passing through the slots and bent so that their ends project into the sockets, substanti ally as specilied.
5. A comm utator-block for an electric snap xo nectiug-pieces, the upper surfaces of the bosses being parallel with the upper and lower faces of the disk whereby the end of a brush is lifted from the level of the disk when a boss is lying beneath it, substantially as specified.
GEORGE E. THOMAS.
H. R. WILLIAMs, E. J. HYDE.